Hmmm . . .
Interesting question, Adventure. Best source, if you can connect, will be other Webmasters from Thailand. We've got over 300 sponsors listed in our Directory of Gay Income Sources but have never classified them that way. Would recommend you decide on a niche or two within the Gay market that you want to promote with your sites and then verify sponsors, by niche. You can do a text search as we identify the primary niche(s) each sponsor addresses.

Good luck in your quest.